Acute Stress Disorder: This is a short-term condition that can develop after a person experiences a traumatic event. It has similar symptoms to PTSD but occurs immediately after the incident and lasts for a minimum of 2 days to a maximum of 4 weeks.
Flashbacks: These are intense, often distressing relivings of past traumatic events as if they were happening in real-time. They're one of the hallmark symptoms of PTSD.
Dissociation: This is a psychological experience where someone feels disconnected from their thoughts, feelings, memories or sense of identity. It's often used as a coping mechanism for trauma and can be experienced by those with PTSD.